Simple cube...with movable nodes

[rgarand]

Hello everyone,

I have a simple question to ask and I hope I get a answer like "The GDL object in in the Special Edition Library" or something like that.

I am looking for a simple cube, which I know is in the Basic Shapes part of the ArchiCAD library...but I would like to move each corner node of the cube independently. This is a very typical thing that can be done in the 3D studio's and Cinema 4D programs, but in CAD programs it seems a bit more complicated. I know straight autocad can not even accomplish this task.

Has anyone developed an object that can do this?

All I want to do is draw a slab and take the bottom nodes of this slab, slide them in the x/y direction to make a trapazoid type object and move on...I know I can make it in profiler and the GDL tools plugin...but why can't I do this with the slab object.

Any thoughts?

[Anonymous]

Thought of making the Slab From a Very flat roof and adjusting the "Roof edge angle". I have not tried this and I do not know how "flat" you can make a roof.

[Djordje]

Jay wrote:
Thought of making the Slab From a Very flat roof and adjusting the "Roof edge angle". I have not tried this and I do not know how "flat" you can make a roof.

This is the way for trapezoidal shapes. Roof can be flat (angle zero)

[Frank Beister]

It is in so far a bit complicated, because you can't move hotspots in 3 directions at the same point. You have to use 2 for each corner. makes 16 for a cube, if it should be free editable. Many points around in 3D.

But if you can live with this, here comes the next: If you change one point others have to change simultaniously too, because every 4 have to be complanar. Otherwise the surfaces are not planar and split into 2 triangulars, from which you don't know, how they are generated (points 1/2/3+3/4/1 or 1/2/4+2/3/4).

Not easy to make the parameters changing by dragging another (special theme ), but much more complicated is the calculation in the 3D.

One editing solution would be to define the "cube" by 6 moveable points on the 6 surfaces and 12 angles to define their inclination. This is in deed a lot of math, if you need hotspots at the edges. Without, it's not so much, because you can use simple CUTPLANES.

[rgarand]

F.

Thanks for the explaination...not really what I wanted to hear, but a great techincal explaination. I often wondered if moving points in 3D made the object (faces) more complex. Sounds like it does...

[Frank Beister]

One I have for you: Trigon

No cube, just a triangle, but you can combine them. Identical positioned hotspots in space of joining triangles can be dragged simoultaneous, if all are selected.

[david nicholson-cole]

rgarand wrote:
I am looking for a simple cube, which I know is in the Basic Shapes part of the ArchiCAD library...but I would like to move each corner node of the cube independently. This is a very typical thing that can be done in the 3D studio's and Cinema 4D programs, but in CAD programs it seems a bit more complicated. I know straight autocad can not even accomplish this task.

do you mean something like this? wrote it tonight after reading your post. If its not here, then i am getting the attachment technique wrong.

[Frank Beister]

That's tricky David, but the "cube" has no plain surfaces. And you can't control the way the surfaces are arched.

BTW: As you use 2 points for the three parameters of each corner: The manual fails in the point one could change more than two parameters with one hotspot. Right?

[david nicholson-cole]

F. wrote:
That's tricky David, but the "cube" has no plain surfaces. And you can't control the way the surfaces are arched.
BTW: As you use 2 points for the three parameters of each corner: The manual fails in the point one could change more than two parameters with one hotspot. Right?

If you have a fully deformable cube, you are going to get curved surfaces. If you select the ROUGH option, you see the planes in the faces of the cube.

I am not sure why you say each point has only 2 parameters. Its obvious when looking at it in 3D that it has X, Y and Z hotspots.
If one UNHIDES the X,Y,Z parameters, someone could write in specific dimensions.
===davidnc

[Frank Beister]

I am not sure why you say each point has only 2 parameters. Its obvious when looking at it in 3D that it has X, Y and Z hotspots.

My question was not clear enough:
The GDL manual says, you may assign to one position in space three groups of hotspot-commands, which create one graphical hotspot, which changes, if dragged, and that's my point, three parameters. In my experience, that's impossible. In your object you use one movebale hotspots for X/Y and one additional for the Z-coordinate. I see this as affirmation for the fault of the manual.

This was no criticism in your cube-object. I understood rgarands ask for a "cube", that he needs something like a polyhedron with 6 surfaces. The rough shaped flexcube is yet quiet similar to this.